SUMMARY We hypothesize differences in composition, size, diameter and surface coating of engineered nanomaterials (ENM) will modulate the in vivo deposition, distribution and biologic effects of aerosolized ENM to the lungs and the eyes. In this project, we will systematically test diverse ENM following aerosolization to identify the key characteristics that influence their toxicity. We have chosen to examine health effects in the respiratory tract and the eye, since both organ systems represent the major route of exposure to aerosolized ENM. Our focus will be to create real and relevant exposure scenarios by inhalation to the major classes of ENMs, a common and expected route of exposure. Further, the lungs and the eyes are both current targets of ENM-based therapeutic delivery. Our goal in this proposal is to systematically and quantitatively compare the health effects of nanomaterials with different physicochemical properties on these organ systems using physiologically relevant models. The health effects will include detailed molecular and pathophysiologic changes that will be targeted to zones of ENM deposition and retention. We are well positioned to contribute to the new NHIR consortium efforts on ENM. We have experience working with many of the materials listed. Because a potentially large number of materials will be systematically tested, a tiered paradigm with clear indications for which ENM need in vivo testing will be used. We have a strong publication record of ENM health effects research in vivo and ex vivo, particularly of novel material aerosols including laboratory generated, dry powder and nebulized liquid aerosols. Our team has expertise in metals, metal oxides, carbon particles, carbon nanotubes and 3-dimensional ENM Coupled with this are the novel methods developed in the Van Winkle, Thomasy and Pinkerton laboratories to study site-specific cellular responses and well-characterized methods in corneal and retinal imaging commonly used in physician-based ophthalmology. These novel approaches include microscopic and histologic approaches to localize ENM in tissues as well as the application of microdissection to study ENM retention and site specific gene, protein and cellular responses. Further, all three investigators have the ability to take advantage of a unique resource, the California National Primate Research Center This enables in vitro studies of ENM effects in a model physiologically relevant to humans, nonhuman primate explants and cells. We know that cell lines give divergent results and so the proposed studies in this application will emphasize primary cells or tissue explants for our organs of interest, coupled with in vivo studies of select ENM aerosols as defined by the consortium. The specific aims of our proposal provide novel and innovative methods to measure cell-based cytotoxicity, inflammation and remodeling in both normal and injury repair models of the complete respiratory tract, as well as the cornea and retina.